shithub: libvpx

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Merge "improve integer version of filter"

--- a/vp8/encoder/temporal_filter.c

+++ b/vp8/encoder/temporal_filter.c

@@ -36,27 +36,34 @@

 #define ALT_REF_MC_ENABLED 1    // dis/enable MC in AltRef filtering

 #define ALT_REF_SUBPEL_ENABLED 1 // dis/enable subpel in MC AltRef filtering

+#define USE_FILTER_LUT 0         // use lookup table to improve filter

-#define USE_FILTER_LUT 1

 #if VP8_TEMPORAL_ALT_REF

 #if USE_FILTER_LUT

+// for (strength = 0; strength <= 6; strength++) {

+//   for (delta = 0; delta <= 18; delta++) {

+//     float coeff = (3.0 * delta * delta) / pow(2, strength);

+//     printf("%3d", (int)roundf(coeff > 16 ? 0 : 16-coeff));

+//   }

+//   printf("\n");

+// }

 static int modifier_lut[7][19] =

 {

     // Strength=0

-    {16, 13, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},

+    {16, 13,  4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0},

     // Strength=1

-    {16, 15, 10, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},

+    {16, 15, 10,  3,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0},

     // Strength=2

-    {16, 15, 13, 9, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},

+    {16, 15, 13,  9,  4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0},

     // Strength=3

-    {16, 16, 15, 13, 10, 7, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},

+    {16, 16, 15, 13, 10,  7,  3,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0},

     // Strength=4

-    {16, 16, 15, 14, 13, 11, 9, 7, 4, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},

+    {16, 16, 15, 14, 13, 11,  9,  7,  4,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0},

     // Strength=5

-    {16, 16, 16, 15, 15, 14, 13, 11, 10, 8, 7, 5, 3, 0, 0, 0, 0, 0, 0},

+    {16, 16, 16, 15, 15, 14, 13, 11, 10,  8,  7,  5,  3,  0,  0,  0,  0,  0,  0},

     // Strength=6

-    {16, 16, 16, 16, 15, 15, 14, 14, 13, 12, 11, 10, 9, 8, 7, 5, 4, 2, 1}

+    {16, 16, 16, 16, 15, 15, 14, 14, 13, 12, 11, 10,  9,  8,  7,  5,  4,  2,  1}

 };

 #endif

 static void vp8_temporal_filter_predictors_mb_c

@@ -140,16 +147,14 @@

             int pixel_value = *frame2++;

 #if USE_FILTER_LUT

-            // LUT implementation --

-            // improves precision of filter

             modifier = abs(src_byte-pixel_value);

             modifier = modifier>18 ? 0 : lut[modifier];

 #else

-            modifier   = src_byte;

-            modifier  -= pixel_value;

+            modifier   = src_byte - pixel_value;

             modifier  *= modifier;

-            modifier >>= strength;

             modifier  *= 3;

+            modifier  += 1 << (strength - 1);

+            modifier >>= strength;

             if (modifier > 16)

                 modifier = 16;